Method for manufacturing semiconductor device, and semiconductor device

Abstract

A semiconductor device includes a first MISFET having a first conduction type channel and formed on a semiconductor substrate; a second MISFET having a second conduction type channel and formed on the semiconductor substrate; a first strain film having a first sign strain that covers a region where the second MISFET is disposed; and a second strain film having a second sign strain that covers a region where the first MISFET is disposed. In the semiconductor device, an edge of the second strain film closer to the second MISFET overlaps with part of the first strain film; and the second strain film at a portion where the second strain film overlaps with the first strain film and at a portion extending from the portion, is thinner than the second strain film at a portion that covers the first MISFET.

1. A method for manufacturing a semiconductor device, comprising:
 forming a first MISFET having a channel of a first conduction type in a first active region of a semiconductor substrate; 
 forming a second MISFET having a channel of a second conduction type that is opposite to the first conduction type in a second active region that is separated from the first active region in an in-plane direction; 
 forming a first film having a strain on the semiconductor substrate so as to cover the first MISFET and the second MISFET; 
 patterning the first film such that the first film in a region where the first MISFET is disposed is removed and the first film in a region where the second MISFET is disposed is left; 
 forming a second film having a strain that is opposite to the first, over the semiconductor substrate so as to cover the first MISFET and the patterned first film; 
 thinning an exposed portion of the second strain film by etching the exposed portion to an intermediate position in a thickness direction of the second film, using a first mask pattern that covers the region where the first MISFET is disposed but not the region where the second MISFET is disposed; and 
 removing the second film in the region where the second MISFET is disposed, using a second mask pattern that covers the region where the first MISFET is disposed but not the region where the second MISFET is disposed, after thinning a part of the second film, 
 wherein one of the first mask pattern and the second mask pattern overlaps with at least a part of an edge of the patterned first film and the other one of the first mask pattern and the second mask pattern is separated from the edge in an in-plane direction; and 
 
       wherein, when removing the second film in the region where the second MISFET is disposed, the second film is removed such that a part of the second film is left in a region that has been covered with only one of the first mask pattern and the second mask pattern. 
     
     
       2. The method for manufacturing a semiconductor device according to  claim 1 , wherein the first mask pattern overlaps with the edge of the patterned first film and the second mask pattern is separated from the edge in an in-plane direction. 
     
     
       3. The method for manufacturing a semiconductor device according to  claim 1 , wherein the first mask pattern is separated from the edge of the patterned first film in an in-plane direction and the second mask pattern overlaps with the edge. 
     
     
       4. The method for manufacturing a semiconductor device according to  claim 1 , further comprising:
 forming an etching stop film having etching resistance different from that of the second film on the first film, after forming the first film and before patterning the first film, wherein, when patterning the first film, the etching stop film is also patterned so as to have the same planar shape as the first film; and 
 wherein, when removing the second film, the second film is etched under a condition under which an etching rate of the second strain film is higher than that of the etching stop film. 
 
     
     
       5. The method for manufacturing a semiconductor device according to  claim 1 , wherein the first film has a tensile strain in a case where the second MISFET is an n-channel MISFET, and the first film has a compressive strain in a case where the second MISFET is a p-channel MISFET. 
     
     
       6. The method for manufacturing a semiconductor device according to  claim 1 , further comprising, after removing the second film:
 forming an interlayer insulating film on the first film and the second film; and 
 forming a via hole extending through the interlayer insulating film in a region that has been covered with one of the first mask pattern and the second mask pattern but not with the other one of the first mask pattern and the second mask pattern. 
 
     
     
       7. A method for manufacturing a semiconductor device, comprising:
 forming a first MISFET having a channel of a first conduction type in a first active region of a semiconductor substrate; 
 forming a second MISFET having a channel of a second conduction type that is opposite to the first conduction type in a second active region that is separated from the first active region with an isolation region between the first MISFET and the second MISFET; 
 forming a first film having a first strain over the semiconductor substrate so as to cover the first MISFET and the second MISFET; 
 patterning the first film such that the first film in a first region where the first MISFET is disposed is removed and the first film in a second region where the second MISFET is disposed is left; 
 forming a second film having a second strain that is opposite to the first strain over the semiconductor substrate so as to cover the first MISFET and the patterned first film; 
 thinning the second film by an etching using a first mask pattern that covers the first region; and 
 removing the second film in the second region using a second mask pattern that covers the first region after thinning a part of the second strain film, 
 wherein one of the first mask pattern and the second mask pattern covers at least part of the isolation region and the other one of the first mask pattern and the second mask pattern covers the first region; and 
 wherein the second film is removed such that a part of the second film is left in a third region that has been covered with one of the first mask pattern and the second mask pattern. 
 
     
     
       8. The method for manufacturing a semiconductor device according to  claim 7 , wherein the first mask pattern covers an edge of the patterned first film. 
     
     
       9. The method for manufacturing a semiconductor device according to  claim 8 , wherein an edge of the first mask pattern is apart from the edge of the patterned first film in the direction of the second MISFET. 
     
     
       10. The method for manufacturing a semiconductor device according to  claim 7 , wherein the second mask pattern is apart from an edge of the patterned first film in the direction of the first MISFET. 
     
     
       11. The method for manufacturing a semiconductor device according to  claim 7 , wherein the first film has a tensile strain in a case where the second MISFET is an n-channel MISFET, and the first film has a compressive strain in a case where the second MISFET is a p-channel MISFET. 
     
     
       12. The method for manufacturing a semiconductor device according to  claim 7 , further comprising, after removing the second film:
 forming an interlayer insulating film over the first film and the second film; and 
 forming a via hole extending through the interlayer insulating film in the third region.